Molecular Characterization of Pancreatic Simple Mucinous Cysts With GNAS Mutation: A Case Report and Literature...

Pancreatic simple mucinous cysts (SMCs) are characterized by cystic lesions >1 cm in size, lacking ovarian-type stroma and lined by a single layer of bland epithelium. Although SMCs are typically considered benign, sporadic cases with KRAS mutations suggest its potential inclusion within the spectrum of low-grade mucinous neoplasms. This study reported a case of pancreatic SMC with co-occurring KRAS and GNAS mutations to discuss their potential implications in the management of pancreatic cystic lesions.

A 54-year-old woman with a 5-year history of pancreatic cysts was initially diagnosed with a branch-duct intraductal papillary mucinous neoplasm presented with abdominal distension. Imaging revealed a rapidly enlarging cystic lesion, prompting spleen-preserving distal pancreatectomy. Targeted amplicon sequencing was performed on the resected cystic wall and background pancreatic tissues. In addition, a literature review of 127 reported SMC cases was conducted to analyze demographics, imaging findings, pathologic findings, and genetic mutations.

Histopathologic analysis confirmed SMC, and genetic testing revealed KRAS and GNAS mutations in the cyst walls. At 32 months after surgery, the patient remained recurrence-free. The median age of the 127 patients was 66 years. The common imaging features included cyst enlargement and wall enhancement. KRAS mutations were found in 35% of the 65 cases, and our case is the first to report GNAS mutations.

This is the first report of pancreatic SMC with co-occurring KRAS and GNAS mutations. SMC should be considered a differential diagnosis of pancreatic cystic lesions. Surgical intervention may be warranted based on findings.